The invention relates to a method and an apparatus for the automated testing of the flash point in the closed crucible and can be used to determine the flash point of flammable liquids, liquids with suspended solids, lubricating oils, liquids, which tend to form a surface film under experimental conditions, and other liquids.
The determination of the flash point of a liquid is an important criterion for assessing whether a material is a fire or explosion risk. The flash point is the lowest temperature, corrected to a barometric pressure of 101.3 kPa, at which the vapors of a sample will be ignited by an igniting flame under the specified experimental conditions. Flash point test equipment was standardized internationally, in order to make these flash point determinations comparable, even when they are made at different sites.
For this purpose, the methods of Pensky Martens (such as those of DIN 51758, ASTM D 93, ISO/EN 2719), Abel (such as those of IP 113, ISO 13726), Abel Pensky (such as those of DIN 51755/53213) and Tag (such as that of ASTM D56) with a closed test insert, are the most widespread worldwide at the present time because of the good reproducibility. All of the important instrument dimensions, such as the heating and measuring conditions, are set down in these standards. In this connection, an important instrument element is the test insert, consisting of crucible and closing lid with a rotary slide valve for freeing the openings of the test lid for an igniter dipping into the vapor space.
Pursuant to the known state of the art, the flash points, because of the rationalization required, are determined predominantly with automated equipment. It is a disadvantage of the known methods that the automation extends only to the heating process, the ignition attempts and the determination of the flash point and only inadequately to the preparatory phase of changing the sample.